146 LOIMIA. 



from the structure of the anterior border, the arrangement of the ventral shields, 

 their lateral pieces and the coloration. The Terebella gigantea of De Quatrefages, 

 however, belongs to another species, whilst his T. prudens and T. pectoralis agree 

 with T. conchilega. 



Cunningham 1 describes four long, double nephridial tubes as occurring in segments 

 6 — 9 ; their internal openings are behind the fascicles of bristles in 5 — 8. 

 Membranous nephridial sacs are also present in segments 10 — 13, and they are inseparable 

 from one another. He found both series in communication, forming a wide, continuous 

 longitudinal tube from segments 6 — 13. Openings to the exterior were found in segments 

 6 — 9. The author draws attention to the fusion of the nephridia as approaching the 

 condition in the vertebrates. 



A careful account of this form is given by De St. Joseph (1894). He states that the 

 intestine is fixed dorsally by a single mesentery, but two occur inferiorly, the blood 

 contains minute corpuscles (hematies), and that the heart holds a cardiac body. The 

 ventral nerve-cord has a neural canal containing a brownish fluid in the thoracic 

 region. In the anterior thoracic chamber are three pairs of segmental organs, first to 

 third segment, and two in the fourth, the canal opening on the fourth segment. Through 

 these the generative elements do not pass, for they do not enter the anterior chamber. 

 There are, however, four pairs of larger greenish segmental organs in the posterior 

 thoracic chamber in segments 6, 7, 8 and 9. Their ciliated funnels communicate with 

 the coelom, and join the nephridial canals, which open on the papillse below the bristle- 

 bundles in these segments. This author 2 found a Polynoid (Harmothoe picta, De St. Jos.) 

 commensalistic in the tube of L. conchilega. 



Dr. Blrington 3 (1908) describes the larva of this form (formerly termed Wartelia by 

 Griard and Nordenskiold), and he corrects various misinterpretations, such as that the 

 dorsal organ, which the two authors just mentioned supposed to be ova, is in reality a 

 glandular structure for secreting the temporary transparent tube of the annelid. The 

 bilobed buccal organ he found to be muscular, not glandular. It is interesting that so 

 long ago as 1851 Busch 4 figured this stage. 



Arnold Watson 5 (1916) furnishes an interesting account of a small L. conchilega, 

 which ingeniously added a large fragment of gravel on its tube by supporting it with its 

 tentacles whilst it was fixed by sand and cement manipulated by the lips, and this though 

 the gap was too large to admit the fragment. 



Genus CXLVII. — Loimta, Malmgren, 1865. 



Cephalic lobe with inconspicuous dorsal collar ; large post-oral lamella. Body 

 typical. BranchiaG three pairs, the first the largest, arborescent, with numerous short 

 ultimate divisions. Seventeen pairs of setigerous processes ; bristles with winged tapering 



1 'Quart. Journ. Micr. Sci./ vol. xxviii, p. 248, pi. xviii, figs. 10 — 14. 



2 ' Ann. Sc. nat./ 7 e ser., t. v, p. 172, pi. viii, figs. 44—47, and ibid., 8 e ser., t. v, p. 233. 



3 < La Cellule/ t. xxv, p. 103, 1 plate. 



4 ' Beobach. u. An at. u. Entwickl. einiger Wirbell. Th./ Taf. xi, fig. 7. 



5 ' Journ. Roy. Micros. Soc./ June, 1916, p. 253, with two text-figures. 



